sirdabalot
Posts: 5
Joined: Wed Nov 14, 2012 9:42 pm

Not enough power from hub?

Wed Nov 14, 2012 9:53 pm

I hope I'm posting this in the right section.

So, I have a powered usb hub that is being supplied by a 2A charger, my pi is also being supplied by 2A, but the hub seems to somehow run out of power or something, plugging just my keyboard and mouse into the hub work fine but adding anything more stops it working, could someone help me?

Pi model B rev 1.0.

Link to the hub I have; https://www.modmypi.com/shop/New-Link-4 ... Adaptor%29.

notarat
Posts: 106
Joined: Wed Sep 12, 2012 12:32 pm

Re: Not enough power from hub?

Thu Nov 15, 2012 3:54 pm

Could very well be a cheap power supply for the hub. I've seen plenty of them over the years that do not put out the power levels for which they are rated.

sirdabalot
Posts: 5
Joined: Wed Nov 14, 2012 9:42 pm

Re: Not enough power from hub?

Thu Nov 15, 2012 5:11 pm

notarat wrote:-Snip-
Thanks for your reply, I will try some crazy hax0rz tomorrow. :)

Frodo1B
Posts: 18
Joined: Sat Nov 03, 2012 12:09 am

Re: Not enough power from hub?

Thu Nov 15, 2012 6:30 pm

Does the RPi start with just the USB hub connected and nothing else? In other words is the hub back powering the RPi through the USB connector and perhaps due to power mismatch is there contention between supplies?

sirdabalot
Posts: 5
Joined: Wed Nov 14, 2012 9:42 pm

Re: Not enough power from hub?

Thu Nov 15, 2012 6:46 pm

Frodo1B wrote:Does the RPi start with just the USB hub connected and nothing else? In other words is the hub back powering the RPi through the USB connector and perhaps due to power mismatch is there contention between supplies?
How do I find out if there is a feedback/contention issue?

Frodo1B
Posts: 18
Joined: Sat Nov 03, 2012 12:09 am

Re: Not enough power from hub?

Thu Nov 15, 2012 7:12 pm

Well I would first find out if the RPi boots just by adding the hub's usb connector to the RPi without the normal power connector connected to the RPi's power supply.

It should not start, if it does then your hub backfeeds power to the RPi, if not then this is not the issue. If it does then .....

sirdabalot
Posts: 5
Joined: Wed Nov 14, 2012 9:42 pm

Re: Not enough power from hub?

Thu Nov 15, 2012 7:14 pm

Frodo1B wrote:-Snip-
Well, in that case, there is no feedback from the hub.

sirdabalot
Posts: 5
Joined: Wed Nov 14, 2012 9:42 pm

Re: Not enough power from hub?

Sat Nov 17, 2012 1:50 pm

Hmm, I change what I said, monitoring the test points tells me that there is 0.5v of feedback, could this be a problem? If so I will make a buffer.

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